ATHENS (Reuters) - Wall Street bank JP Morgan has filed two lawsuits over its investment in fintech Viva Wallet, the latest twist in a legal dispute between the two sides over how to value the Greek business.

A source with knowledge of the matter told Reuters that JP Morgan filed a lawsuit in Greece on Jan. 2 seeking 916 million euros ($944 million) over allegations that Viva's CEO, Haris Karonis, and three other executives "deprived JPMorgan of the value of its 2022 investment in Viva through unlawful actions from March 2022 onwards".

In an emailed statement, Karonis confirmed the two lawsuits and denounced them as an act of intimidation. He did not give details of either suit.

"These proceedings are simply the latest step in JPM's concerted effort to depreciate Viva's value, to preclude it from expanding in the United States and elsewhere, and intimidate its directors," the statement said.

The U.S. bank bought a 48.5% stake in Viva Wallet, which is used by businesses in southern Europe, for about $800 million in 2022. Werealize (WRL) owns 51.49%.

Under the terms of the deal, WRL loses its right to reject any JP Morgan offer to take control of Viva if the business is valued at below 5 billion euros ($5.4 billion) by July 30, 2025.

Both sides claimed success in June when a London judge issued a decision on how the business should be valued, after they sued each other on the valuation of the joint business.

JP Morgan also filed a case in UK this week against Werealize.com, which claims it breached shareholder agreements by causing Viva not to respect the obligation to obtain JPMorgan's consent before taking certain specified significant business actions, the source said.

WRL did not immediately respond to a request for comment.